[Exim] Unexpectedly odd interaction of Exim & Fetchmail

Before recently playing with my exim configuration, the first few
lines of a mail message used to be:

>From exim-users-admin@??? Fri Dec 21 14:53:27 2001
Envelope-to: derek@othello
Received: from casio.othello.dyn.ca ([127.0.0.1] helo=localhost)
by casio.othello.dyn.ca with esmtp (Exim 3.32 #1 (Debian))
id 16HVjT-0000R7-00
for <derek@othello>; Fri, 21 Dec 2001 14:53:27 -0500

Now, I get:

>From fetchmail@??? Mon Dec 24 10:34:53 2001
Envelope-to: derek@othello
Received: from fetchmail by casio.othello.dyn.ca with local (Exim 3.32
#1 (Debian))
id 16IX7r-0002WK-00
for <derek@othello>; Mon, 24 Dec 2001 10:34:51 -0500


"fetchmail " is the correct userid of the fetchmail process on my
system (though it's not running on netcom.ca, that's understandable),
but why is it suddenly using that as the sender, not the real sender?
I can't figure out what's changed - this looks like the mail is no
longer being picked up by the SMTP process out of inetd, but the
system and exim logs show it is.
--
derek